Anne Arundel County (modern spelling adds an 'e' to her first name of "Ann" and a second 'L' to the family name of "Arundell" – but the old traditional spelling of her name is still used in the title of the local historical society, the Ann Arundell County Historical Society) was originally part of St. Mary's County in the southern portion of the Province of Maryland which had first been settled by the arriving settlers in 1634. In 1650, the year after Lady Ann Arundell's death, the County separated from St. Mary's and "erected" into its own jurisdiction and became the 3rd of the 23 Maryland counties. Between 1654 and 1658, the County was known as "Providence" by many of its early settlers.[citation needed]

Between 1694 and 1695, the provincial capital of Maryland was moved from St. Mary's City along the northern shore of the Potomac River across from the southern colonial border with the Province of Virginia in St. Mary's County further north along the western shore of the Chesapeake Bay, midway in the colony to Annapolis in Anne Arundel County. Prior to the move, Annapolis was known as "Providence".[4]

On May 22, 1830, the inaugural horse-drawn train of the Baltimore and Ohio Railroad travelled the 13 miles (21 km) of the newly completed track from Mount Clare Station in southwestern Baltimore City to Ellicott Mills, (now Ellicott City), then in the Western or Howard District (now Howard County) of Anne Arundel County. This was the first regular railroad passenger service in the United States.[citation needed] In 1831, land west of the railroad was considered the Howard District of Anne Arundel County. In 1851, The Howard District was broken off to form Howard County, now the 21st county in Maryland (of 23).[5]

According to the U.S. Census Bureau, the county has a total area of 588 square miles (1,520 km2), of which 415 square miles (1,070 km2) is land and 173 square miles (450 km2) (29%) is water.[7] Anne Arundel County is located to the south of the city of Baltimore.

Anne Arundel County originally included all of the land between the Patuxent River and the Patapsco River (mainstem and South Branch) upstream to their headwaters on Parr's Ridge. The northwestern section of this long tract later became Howard County, with the border between the two running very close to the Atlantic Seaboard fall line. As a result, Anne Arundel County lies almost entirely within the Atlantic Coastal Plain while Howard County is almost entirely within the Piedmont province.

Elevations in Anne Arundel County range from sea level at the Chesapeake and tidal tributaries to approximately 300 feet (91 m) in western areas near the fall line.[9] The terrain is mostly flat or gently rolling, but more dramatic banks and bluffs can be found where waterways cut through areas of higher elevation.

With the exception of the very limited extent of Piedmont underlain by Precambrian to early Paleozoicmetamorphic rock, all of the county is underlain by thick deposits of gravel, sand, silt, and clay dating from the early Cretaceous to Holocene times.[10] Most of these sediments are unconsolidated but include local formations of sandstone, especially in the Pasadena area.[11]

Anne Arundel County has a humid subtropical climate, with hot summers and cool winters. Annual precipitation averages around 40 inches (100 cm) per year throughout the county, with a fairly even distribution throughout the year. Annual snowfall totals around 20.1 inches (51 cm) on average at BWI Airport, which has an elevation of 156 feet (47.5 m) above sea level.[12] Slightly colder winter temperatures and higher snowfall are experienced at the higher elevations, with slightly lower snowfall closer to sea level.[13] According to the most recent USDA Hardiness zone maps, the lowland areas of the county fall into Zone 7b, with an expected annual minimum temperatures of 5 to 10 °F (−15 to −12 °C), while higher areas fall into Zone 7a, with expected annual minima of 0 to 5 °F (−18 to −15 °C).[14]

Anne Arundel County has had a charter government since 1965. The government consists of a County Executive and a seven-member County Council. The County Executive and Council members are elected in the same years Maryland conducts its gubernatorial and legislative elections, and may serve a maximum of two consecutive terms.

The Democrats are also the largest party by number of registered voters, but the large number of Republican-leaning independents means Republicans win more county-wide elections than in other mostly-suburban counties in Maryland. However Democrats are the dominant party in Annapolis city elections. In the 2016 Presidential Election Anne Arundel County narrowly went for Hillary Clinton over Donald Trump by 1,565 votes.[15]

The County Executive oversees the executive branch of the County government, which consists of a number of offices and departments. The executive branch is charged with implementing County law and overseeing the operation of the County government. The next election will be in 2018.

As of the census[24] of 2000, there were 489,656 people, 178,670 households, and 129,178 families residing in the county. The population density was 1,177 people per square mile (455/km²). There were 186,937 housing units at an average density of 449 per square mile (174/km²). The racial makeup of the county was 81.24% White, 13.57% Black or African American, 0.30% Native American, 2.29% Asian, 0.06% Pacific Islander, 0.85% from other races, and 1.69% from two or more races. 2.63% of the population were Hispanic or Latino of any race. 17.7% were of German, 13.1% Irish, 10.5% English, 8.1% United States or American and 7.0% Italian ancestry.

There were 178,670 households out of which 34.90% had children under the age of 18 living with them, 57.20% were married couples living together, 11.10% had a female householder with no husband present, and 27.70% were non-families. 21.30% of all households were made up of individuals and 6.40% had someone living alone who was 65 years of age or older. The average household size was 2.65 and the average family size was 3.09.

In the county the population was spread out with 25.20% under the age of 18, 8.10% from 18 to 24, 32.80% from 25 to 44, 23.90% from 45 to 64, and 10.00% who were 65 years of age or older. The median age was 36 years. For every 100 females there were 99.10 males. For every 100 females age 18 and over, there were 97.10 males.

As of Census 2010 the population was 537,658. The ethnic and racial make-up of the county population was 72.42% Non-Hispanic white, 15.52% black, 0.31% Native American, 3.41% Asian, 0.16% Non-Hispanic of some other race, 2.37% non-Hispanics of two or more races and 6.12% Hispanic.

As of the 2010 United States Census, there were 537,656 people, 199,378 households, and 139,262 families residing in the county.[25] The population density was 1,295.9 inhabitants per square mile (500.3/km2). There were 212,562 housing units at an average density of 512.3 per square mile (197.8/km2).[26] The racial makeup of the county was 75.4% white, 15.5% black or African American, 3.4% Asian, 0.3% American Indian, 0.1% Pacific islander, 2.4% from other races, and 2.9% from two or more races. Those of Hispanic or Latino origin made up 6.1% of the population.[25] In terms of ancestry, 23.3% were German, 18.6% were Irish, 12.3% were English, 7.4% were Italian, 5.0% were Polish, and 4.4% were American.[27]

Of the 199,378 households, 34.6% had children under the age of 18 living with them, 53.1% were married couples living together, 12.1% had a female householder with no husband present, 30.2% were non-families, and 23.7% of all households were made up of individuals. The average household size was 2.63 and the average family size was 3.11. The median age was 38.4 years.[25]

The median income for a household in the county was $83,456 and the median income for a family was $97,557. Males had a median income of $63,187 versus $48,750 for females. The per capita income for the county was $38,660. About 3.3% of families and 5.3% of the population were below the poverty line, including 6.9% of those under age 18 and 5.5% of those age 65 or over.[28]

In 2000, the median income for a household in the county was $61,768, and the median income for a family was $69,019 (these figures had risen to $79,294 and $91,071 respectively as of a 2007 estimate[30]). Males had a median income of $43,747 versus $32,348 for females. The per capita income for the county was $27,578. About 3.60% of families and 5.10% of the population were below the poverty line, including 6.30% of those under age 18 and 5.80% of those age 65 or over.

Sandy Point State Park is located at the end of the Broadneck peninsula near the west end of the Chesapeake Bay Bridge. It features a beach and marina and hosts many festivals and special events throughout the year.[38]Helen Avalynne Tawes Garden is located at the Department of Natural Resources headquarters in Annapolis. The 5 acre garden features representations of the state's various geographic areas.[39] The county also contains some of the easternmost portions of Patapsco Valley State Park, consisting of mostly undeveloped areas of forest and wetlands along the lower Patapsco River.